An antenna mounted in a mobile device is configured to be electrically connected to a main board (RF board) of a main body. For example, in the case of a general monopole antenna device, a feeding end (or a feeding pin) of an antenna radiator is electrically connected to a feeding pad of a main board, whereas a Planar Inverted F Antenna (PIFA) has feeding and grounded configurations.
Therefore, in the case of the PIFA, a feeding end drawn out from an antenna radiator is connected to a feeding portion electrically connected to an RF connector of a main board, and a grounded end (or a grounded pin) drawn out from the antenna radiator is connected to a ground portion electrically connected to a ground portion of the main board.
In general, the antenna radiator of the PIFA device is fixed to an antenna carrier and the antenna carrier is installed in the main board. This is because the radiating performance of the antenna is improved as the size of the radiator, the area of a grounded surface, and the height between the emitter and the grounded surface increase.
In addition, the emission through the antenna is divided into emission in a “near field” and emission in a “far field”. The antenna receive sensitivity in a real calling status belongs to the “far field”. The “far field” is in proportion to the “near field”, and thus, as the strength of the “far field” increases, the strength of the “near field” also increases.
In addition, since the “near field” exerts a direct influence on an SAR value, it is desirable that the mobile device antenna is designed to have the strongest “far field” and the weakest “near field.”